Generally, fuel is introduced into a combustion chamber for a gas turbine by one or more fuel injectors. Various fuels can include natural gas, coal slurry, and other fossil fuel-based, carbon-based or hydrogen-based fuels. Fuel injectors typically have a limited life span due to their constant exposure to high temperatures. High temperatures are caused by radiant heat from the partial combustion of fuel and oxygen within the combustion chamber. When a fuel injector begins to show heat damage or otherwise fails due to overheating, the associated gas turbine must be shut down to permit repairs or replacement of the damaged fuel injector.
At least one conventional fuel injector uses water circulation to cool particular portions of the fuel injector. In such a fuel injector, cooling can be achieved by circulating water in one or more cavities in the tip of the fuel injector and/or within a jacket surrounding some or all of the body of the fuel injector. However, conventional fuel injectors using water cooling require operating and maintaining associated water circulation systems, which increase the cost to operate the gas turbine.
Accordingly, there is need for methods and apparatus for increasing the life of a fuel injector. There is a further need for providing a sacrificial shield for a fuel injector. There is a further need for providing shielding to a fuel injector associated with a combustion device.